This invention relates to an optical disk drive.
Generally, an optical disk drive writes and reads data on an optical disk by means of a laser beam. The optical disk drive includes a light source module that emits the laser beam and an optical head carrying an objective lens that converges the laser beam on a small light spot on the optical disk.
The tracking operation of the optical disk drive includes (1) a rough tracking operation and (2) a fine tracking operation. The rough tracking operation is accomplished by moving the optical head crossing the tracks of the optical disk. The fine tracking operation is accomplished by minutely moving the light spot on the optical disk. For this purpose, a galvano mirror is provided in a light path between the light source module and the objective lens. By rotating the galvano mirror, the angle of incidence of the laser beam incident on the objective lens is changed, so that the light spot on the optical disk is moved.
Generally, a galvano mirror is mounted to a rotatable mirror holder. The mirror holder is accommodated in a stator. In order to rotate the mirror holder, coils are provided to opposing ends of the mirror holder. Magnets are provided to the stator so that the magnets are faced with the coils. The galvano mirror is rotated by an electromagnetic induction caused by current flow in the coils and a magnetic field caused by the magnets.
For feeding electricity to the coils of the mirror holder, the coils are connected to terminals (provided on the stator) via wires. The wires are laid between the mirror holder and the stator. Thus, when the galvano mirror is rotated, it causes a deformation (bending or twisting) of the wires. Such deformation of the wires may disturb the rotation of the galvano mirror.
Accordingly, there is a strong demand of a galvano mirror unit having an electrical feeding path which does not disturb the rotation of a galvano mirror.